Technical Field
The present invention relates to a semiconductor device and a manufacturing method for a semiconductor device.
Related Art
An insulated gate bipolar transistor (IGBT) is a type of power device whose importance is recently steadily increasing with the demand to build a low energy society. In particular, lateral IGBTs can be incorporated into ICs and are therefore expected to have diverse applications.
The following are known as examples of technology for improving the withstand voltage of an IGBT. Japanese Patent Application Laid-Open (JP-A) No. 2010-186878 describes forming a trench in a wafer surface between an emitter region and a p+ collector region, embedding a trench-embedded insulating film in the trench region so as to bend a drift region that supports the withstand voltage, and effectively elongating the drift length.
There is a tradeoff relationship between output characteristics and withstand voltage characteristics in IGBTs. Namely, when the saturation voltage between the collector and emitter is lowered and the loss is decreased, the withstand voltage between the collector and emitter is reduced. However, when the withstand voltage between the collector and emitter is raised and the margin to destruction by overvoltage is increased, the saturation voltage between the collector and emitter is increased. This tradeoff relationship has meant that the overall performance of conventional lateral IGBTs cannot be considered sufficiently high.